title: Anti-CCP antibodies, rheumatoid factors and anti-keratin antibodies: clinical value in established rheumatoid arthritis.
abstract: BACKGROUND
  It is well documented that in early rheumatoid arthritis, anti-CCP antibodies have better diagnostic value than rheumatoid factors and anti-keratin antibodies. However, their role is less well defined in patients with established or long duration disease.
  
  
  OBJECTIVE
  To evaluate and to compare diagnostic performances of anti- CCP, anti-keratin, IgM and IgA rheumatoid factors in established rheumatoid arthritis.
  
  
  METHODS
  In a cross-sectional study, 90 patients with established rheumatoid arthritis and 100 controls were tested for these autoantibodies. The association of these markers with disease activity and severity was investigated. The sensitivity and specificity were calculated for each of four tests, using the clinical diagnosis as the gold standard.
  
  
  RESULTS
  The anti-CCP and IgM rheumatoid factor exhibited the best diagnostic value. None of the tested antibodies had any significant association with the disease activity score (DAS28). After adjustment by multiple linear regression, only anti-CCP positivity was found to be significantly associated with erosive disease.
  
  
  CONCLUSIONS
  In long duration rheumatoid arthritis, anti-CCP and IgM rheumatoid factor have similar diagnostic value. However anti- CCP are useful in seronegative patients. They are also a reliable marker of severe erosive disease.
authors.affiliation: Department of Immunology, Charles Nicolle Hospital, Tunis, Tunisia.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Amri
authors.forename: Imen
authors.initials: I
authors.lastname: Sfar
authors.forename: Hajer Skhiri
authors.initials: HS
authors.lastname: Ounallah
authors.forename: Tarek
authors.initials: T
authors.lastname: Dhaouadi
authors.forename: Noura
authors.initials: N
authors.lastname: Bel Hadj
authors.forename: Leila
authors.initials: L
authors.lastname: Abdelmoula
authors.forename: Rafik
authors.initials: R
authors.lastname: Zouari
authors.forename: Khaled
authors.initials: K
authors.lastname: Ayed
authors.forename: Yosr
authors.initials: Y
authors.lastname: Gorgi
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000175:diagnosis* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007633:Keratins / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D007633:Keratins